Exhaust system

ABSTRACT

An elongate core member is disclosed defining indentations therein which afford a fluted interior passage, the walls of the indentations being relatively thin at times defining openings therethrough. The core member is disclosed in a folded configuration enclosed by a housing with a cushioned lining pad separating the core member from the housing. A screen is positioned in the duct which is partially defined by the core, to assure the passage of only particles of minimum size.

, United States Patent [72] Inventor E'mmetj. Corn, .lr.

Lakewood, Calif. [21] .Appl. No. 881,826 [22] Filed Dec. 3, 1969 [451 Patented July 6, 1971 [73] Assignee Mini-Fold Scooter Co., Inc.

[54] EXHAUST SYSTEM 3 Claims, 3 Drawing Figs.

[521 11.8. CI 181/50, 181/54,181/56 [51] 1nt.Cl. F0111 1/10, FOln 1/04 [50] Field ofSearch 181/35.3, 61-63, 50,56, 46, 53,54, 71, 36.3

[56] References Cited UNITED STATES PATENTS 1,918,149 7/1933 Sullivan 181/71 UX 1,988,048 1/1935 Peik 181/50 2,004,865 6/1935 Grison 181/36 (.3) 2,070,543 2/1937 Cary et a1. 181/63 UX 2/1940 Muller ..I 181/63 UX 10/1961 Ewashuk 181/61 X 4/1967 Marx 181/59 FOREIGN PATENTS 12/1939 France 181/42 4/1951 France 181/59 11/1953 France..... 181/61 11/1959 Germany.. 181/54 12/1956 ltaly 181/48 2/1961 ltaly 181L48 Primary Examiner-Robert S. Ward, Jr. An0rney-Nilsson, Robbins, Wills and Berliner BIZC.

PATENTED JUL SIHII 3,590,946

II II II II 1| 1| II I ll II II N ll ll III- l VFNTUR.

L-MMET J. coR/v JR.

EXHAUST SYSTEM,

BACKGROUND AND SUMMARY OF THE INVENTION Noise attendant .the operation of various vehicles has become a problem of ever-increasing significance. The problem is particularly acute with regard to two-wheel vehicles which must be designed with a view toward restricting the size and weight of almost every component part. Additionally, such vehicles frequently employ high-speed engines which tend to create high frequency noise which is sometimes more difficult to effectively muffie or dissipate.

In addition to the noise problem presented by two-wheel vehicles, it is important that their exhaust systems block the passage of hot particles which can cause considerable'damage. In general, the total length of an exhaust system for a twowheel vehicle is relatively short, compared to that of the exhaust system for an automobile. In the past, conventional practice has involved the provision of a screen in the exhaust system of a two-wheel vehicle to function as a spark arrester." In the past, the screen in a conventional exhaust system tends to become clogged with particles carried by the exhaust with the result that it must be frequently changed or cleaned to avoid serious reduction in the volumetric efficiency of the engine. In this regard, it is important to understand that conventionalexhaust systems have often offered substantial impedance to the flow of gases, even when new and clean, with the result that engine efficiency is substantially diminished.

In general, the present invention may be embodied in a form of exhaust system which effectively reduces engine noise, offers relatively small resistance to the flow of gases and reduces solid particles (products of combustion) to a very small-size with less clogging of the spark arrester" screen. Specifically, the system may take the form of a folded core defining a fluted duct or passage with plural transverse ridges spaced therealong. A method of producing the cores with'the desired fluted configuration is set forth below in detail. The core is fixed within a housing which defines'a passage thereto for exhaust products of combustion, and additionally supports a lining pad adjacent to the core and a spark arrester" screen downstream from the core.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, which constitutes a part of this specification, an exemplary embodiment demonstrating various objectives and features hereof is set forth as follows:

FIG. 1 is a sectioned perspective view of an exhaust system provided in accordance herewith;

FIG. 2 is a longitudinal sectional view taken through the structure of FIG. 1; and

' FIG. 3 is a transverse sectional view taken through a fragment of the system of FIG. I.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT Referring initially to FIG. 1, there is shown an internally fluted folded core which is supported within a housing 12. A cushioned lining pad 14 lies between the core 10 and the housing 12. In general, exhaust gases and other products of combustion are directed to flow through the core 10 from an inlet 16 to an outlet 18, then'passing through a spark arrester structure 20 which assures that no particles are passed which are above a predetermined size. In the operation of the system, the core 10 functions to effectively break up solid particle combustion products for passage through the spark arrester structure 20 while concurrently significantly reducing or dissipating sonic energy. Furthermore, it'is to be noted that the system as illustrated in FIG. 1 offers little resistance to the flow of combustion gases with-the result that engine efficiency is not significantly reduced.

Considering the system'as disclosed herein, in greater detail, an intake flange 22 provides for the connection of the system to an engine (not shown). The flange 22 may consist of metal plate, with bores 24 extending therethrough' to receivestuds for an abutting connection. The flange 2 2 is integrally ffixd to an intake duct 26, as by welding, so as "to 'provide a passage through the flange 22 and the duct 26 iritothe h'ous'ing'l2.

Considering the housing 12 more specifically, the duct 26 is integrally connected (as by welding) to aso'mewha't flat flared section 28 which is integral with a body section 30' of somewhat oval cross section, the opposed end of which is integral with another flared section 32 which receives a duct member 34 (containing the spark arrester structure 20):which is in turn connected to a tailpipe 36.

Considering the detailed structure of the core 10, individual pipes or tubes 38, and 42 are end connected in a folded configuration to accomplish a linear passage which is substantially three times thelength of the individual tubes. Specifically, from the orifice or inlet 16 of the tube 38, the flow path is along the length of that tube, then through a junction 44 defined at the ends of the tubes 38 and 40, back through the tube 40 and through a similar junction 46, between the tubes 40 and 42, then through the tube 42 to the flared section 32, the duct member 34 and the tail pipe 36. The left ends of the tubes 40 and 42 (as shown are closed by a plate 48 which is ofsomewhat oval configuration and which defines an internal circular orifice through which the left end of the tube 38- is received. A similar plate 50 is provided at the right ends of the. tubes and passes the tube 42 while closing the ends olltbe,

tubes 38 and 40. The plates 48 and 50 are welded to the hous.-,

ing 12 and the tubes 38, 40 and 42 are welded to theplates-48 and 50. Junctions 44 and 46 may be provided by straps or portions of the tubes 38 and 42 welded to the tube 40 to provide folded passageways.

Each of the tubes 38, 40 and 42 have rows of-indentations 52 which are provided in space quadrature. These indentations are provided to accomplish flutes or risers 54 (FIG. 2) which extend into the internal passages of the tubes 38, 40 and 42 thereby providing defined upstream shoulders 56 and downstream shoulders 58, which include a very thin thickness strap across the cylinder. That is, the individual indentations 52 may comprise simply a strap of metal (of reduced thickness) extending across an arcuate aperture through the tube. The method of forming such indentations or flutes is described in detail below; however, it is important to appreciate that the provision of a plurality of thin strips of metal disposed to traverse or bridge an arcuate orifice in the cylindrical tubes accomplishes effective operation for the system hereof.

The tubes 38, 40 and 42 are produced in production by gang cutting each of the rows of slots or indentations 52. Specifically, a length of tube 60 (FIG. 3) is fixed on a machine table (not shown) then a gang of cutting wheels 62 which may be toothed or simply abrasive, are moved into the tube 60. As a consequence, a strap 64 of metal is formed to bridge an arcuate aperture 66 defined in the tube 60. During the cutting operation, most of the metal on either side of the strap 62 is removed thereby defining openings 68. Thus, the straps 64 may be considered as end-supported breakup members both for sound and for solid particles flowing from the engine as the products of combustion. These members are thus effective to dissipate sonic energy and concurrently reduce solid particles contained in the exhaust stream to a very small size for passage through the spark arrester structure 20.

In the manufacture of exhaust systems in accordance herewith, it may be advantageous to initially form the tubes 38, 40 and 42 in single lengths which are then cut into the desired lengths for use in a specific exhaust system. Such lengths, in the form of the specific tubes 38, 40 and 42 may then be welded in fixed relationship between the plates 48 and 50 to form the desired folded channel. It is to be noted that the plates 48 and 50 may be die-cut, stamped or otherwise formed of steel, being of the same alloy as the tubes 38, 40 and 42.

Generally, the plates 48 and 50 may havea thickness which is less than the thickness of the walls of the tubes 38, 40 and 42. In one successful embodiment hereofftubular members have beenaxse d having a wall thickness of approximately one-six-v these units are enclosed in the pad 14 which completely encircles the assembled core. In general, it has been found desirable to utilize fiber glass as the pad 14 having a relatively loose simply rolled over the core 10. Alternatively, the entire housing 12 may be formed in halves which are flange fastened togetheror welded by a'butt weld. Clearly, a wide variety of possibilities are'evident for the manufacture of the housing I2 with the core therein. I a

The intake structure, including the flange 22 and the duct 26 may be formed as a sub'assembly, as may the duct 34, containing the spark arrester structure and the tail pipe 36. These members may then. be welded to thehousing 12 as indicated by weld beads 70 and 72.

It is to be noted, that thetailpipe 36 is friction fitted over the duct member 34 with a'setscrew 73 for removal of the spark arrester structure 20. In detail, the'spark arrester structui'e'20' includes a pair of rings 74 with a fine-mesh screen 76 affixed therebetween. The combination is then held between the end of the duct member 34 and the tailpipe 36 by engagement with the end of the duct member 34 and a reducing shoulder 80 resulting from the taper in the tailpipe36.

In using the exhaust system hereof, the flange 22 is employed for connection of the unit to an engine, as through an exhaust manifold (not shown). The products of combustion from the engine are then received within the flared section 28 ('FIG. 2) then passing in folded sequence through the tubes 38,

- 40 and 42 to be received in the tapered or flared section 32 for discharge through the duct member 34 containing the spark arrester 20. Thecombination of the plurality of metal straps 64 which are disposed transversely in the ducts 38, 40 and 42 in combination with the folded configuration of the core 10 and the surrounding damper pad 14 has been determined to 7 the sound-dampening pad l4. Additionally, the folded nature of the core-l0 dissipates considerable sonic energy.

As coincidental considerations, it may also be seen that the individual metallic straps 64 (FIG. 3) defining the indentations 54 (FIG. 2) are effective to create turbulence in the flow while concurrently breaking up any solid particles which impact thereon. lt-is to be noted both .withmegard. to sounddeadening considerations, and providing impingement sur faces for solid particles, that the structure as disclosed herein provides for effective impact surfaces for sonic energy and the products of combustion. Specifically, 'sound and combustion products entering the system initially impingeupon the plate 48. Subsequently, impingement is directed to occur inside the tube 38 on the internal surface of the plate 50. Subsequently,

impingement occurs on the internal surface of the plate 48 at the left end of the tube 42: and.lastly impingement occurs to some degree on the walls of the flared section 32. Such a flow path has been found to be exceedinglyfeffective in reducing solid particles which are included in the'products of combustion, to a size for passage through the screen 76 (FIG. I). The mesh size of the screen 76 is such that particles passed therethrough will almost immediately drop to ambient temperature on ex osure thereto Cpnseqluentlg), the scre en 76 will not tend to e clogged or partially c osed y solld particles and the particles passing through there are safe and generally harmless.

In view of the above considerations, it is apparent that a folded-core exhaust system incorporating indentations to provide internal flutes along the passage is an cffectivestructure in combination with a dampening pad and a flame arrester screen for use in association with an vengine to minimize the danger of live sparks or hot particles as well as to reduce the noise by dissipating sound, without substantially impeding the flow of gas therethrough.

What I claim is:

1. An exhaust system for an engine, comprising:

an elongate metal core member defining a fluted passage to receive exhaust from said engine, said core member defining a'folded elongate tube of substantially uniform cross-sectional area, perforated by arcuate gaps transversely defined in the walls thereof and transversely bridged by integral straps of a thickness that is substantially less than the thickness of said tube;

a metal housing enclosing said core member and defining an intake port and an exhaust port, said housing defining a space uniformly larger than said core member; and

a lining pad'of cushionlike material disposed between said core member and said metal housing.

2. An exhaust system according to claim 1 wherein said passage of said elongate metal core is offset'from alignment with said intake port of said metal housing and wherein said metal core member'is folded within a single plane.

3. An exhaust system according to claim 2 further including a screen member affixed'in said housing to receive exhaust from said core member. I 

1. An exhaust system for an engine, comprising: an elongate metal core member defining a fluted passage to receive exhaust from said engine, said core member defining a folded elongate tube of substantially uniform cross-sectional area, perforated by arcuate gaps transversely defined in the walls thereof and transversely bridged by integral straps of a thickness that is substantially less than the thickness of said tube; a metal housing enclosing said core member and defining an intake port and an exhaust port, said housing defining a space uniformly larger than said core member; and a lining pad of cushionlike material disposed between said core member and said metal housing.
 2. An exhaust system according to claim 1 wherein said passage of said elongate metal core is offset from alignment with said intake port of said metal housing and wherein said metal core member is folded within a single plane.
 3. An exhaust system according to claim 2 further including a screen member affixed in said housing to receive exhaust from said core member. 